﻿<p><em>IfcPropertyEnumeration</em> is a collection of simple or measure values that define a prescribed set of alternatives from
which 'enumeration values' are selected. This enables inclusion of enumeration values in property sets. <em>IfcPropertyEnumeration</em>
provides a name for the enumeration as well as a list of unique (numeric or descriptive) values (that may have a measure type
assigned). The entity defines the list of potential enumerators to be exchanged together (or separately) with properties of type 
<em>IfcPropertyEnumeratedValue</em> that selects their actual property values from this enumeration. </p>

<p>The unit is handled by the <em>Unit</em> attribute, see Table 2 for an example of a unitless property enumeration:</p>
<ul>
  <li>If the <em>Unit</em> attribute is not given, than the unit is already implied by the type of <em>IfcMeasureValue</em>
or <em>IfcDerivedMeasureValue</em>. The associated unit can be found at the <em>IfcUnitAssignment</em> globally defined
at the project level (<em>IfcProject.UnitsInContext</em>).</li>
  <li> If the <em>Unit</em> attribute is given, the unit assigned by the unit attribute overrides the globally assigned unit.</li>
</ul>
<p>&nbsp;</p>
<table>
 <tr>
  <td>
   <table class="gridtable">
    <tr>
      <th width="30%"><b>Name</b></th>
      <th width="30%"><b>EnumerationValues</b></th>
      <th width="25%"><b>Type</b> <span style="font-size:smaller">(through <em>IfcValue</em>)</span></th>
      <th width="15%"><b>Unit</b></th>
    </tr>
    <tr>
      <td>PEnum_DamperBladeAction</td>
      <td>Parallel</td>
      <td><em>IfcLabel</em></td>
      <td>-</td>
    </tr>
    <tr>
      <td>&nbsp;</td>
      <td>Opposed</td>
      <td><em>IfcLabel</em></td>
      <td>&nbsp;</td>
    </tr>
    <tr>
      <td>&nbsp;</td>
      <td>Other</td>
      <td><em>IfcLabel</em></td>
      <td>&nbsp;</td>
    </tr>
    <tr>
      <td>&nbsp;</td>
      <td>Unset</td>
      <td><em>IfcLabel</em></td>
      <td>&nbsp;</td>
    </tr>
   </table>
  </td>
 </tr>
 <tr>
  <td><p class="table">Table 2 &mdash; Property enumeration with values, measure types and units</td>
 </tr>
</table>
<blockquote class="history">
HISTORY&nbsp; New entity in IFC2.0, capabilities enhanced in IFC2x.
</blockquote>
<blockquote class="change-ifc2x">
IFC2x CHANGE&nbsp; Entity has been renamed from IfcEnumeration
</blockquote>